Apparatus for hydrocarbon oil conversion



June 23, 1931.

o. H. FAIRCHILD APPARATUS FOR H YD ROCARBON OIL CONVERSION s Shee ts-Sheet 2 Filed 001;. 10. 1927 June 23, 1931. o. H. FAIRCHILD APPARATUS FOR HYDROCARBON OIL CONVERSION s Sheets-Sheet 3 Filed 0c t.- 10, 1927 atented June 23, 1%31 UNITED STATES PATENT OFFICE OSCAR H. FAIRCHILD, OF CHICAGO, ILLINOIS, ASSIGNO'R TO UNIVERSAL OIL PRODUCTS COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF SOUTH DAKOTA APPARATUS FOR HYDROCARBON OIL CONVERSION Application filed October 10, 1927. Serial No. 225,078.

This invention relates to improvements in apparatus for cracking hydrocarbon oil, and refers more particularly to an apparatus especially designed for vapor phase crack ing.

The apparatus comprises generally a tubular structure mounted in a furnace and constructed of a material generally refractory to welding, such as carborundum or the like, characterized by having a relatively high heat conductivity wherein vapors produced in a process of converting hydrocarbon oil under heat are further heated and converted at a cracking temperature.

One object of the invention is to provide an apparatus in which hydrocarbon oil vapors are heated to temperatures high enough to securemaximum conversion. This object is accomplished in the present invention by providing a tubular structure mounted in a furnace constructed of material capable of withstanding excessively high temperature without deterioration, characterized by being refractory to welding while possessing high heat conductivity.

In carrying out the process of vapor phase cracking-a substantial amount of car- "bon and coke is formed which collects on the inside of the'cracking apparatus. This is usual with all vapor phase cracking processes, particularly those carried out in tubular structures. The heat conductivity of the carbon being very lowa substantial accumulation will therefore cause tubes of the conventional type to overheat and thus be damaged. Not only would this cause a shutdown, but an explosion due to the escaping vapors might occur if they escaped in suflicient quantities. I

The tubes in my apparatus being constructed of a refractory material that has an extremely high melting point, such as carborundum tile or the like, will not be damaged from the heat by reason of the accumulation of the carbon, as the tubes are of such character as to withstand much higher heat than tubes heretofore used for the same purpose without damage.

Another feature of the-present invention residesin'the ease with which carbon, coke air into them to cause combustion of the carbon or coke. Since the tubes in my device are of a material highly refractory to burning or melting the above method may be employed without deleterious effects. Such a method is particularly advantageous as the cracking process will not be seriously interrupted by cleaning the tubes as is the case with the conventional type of furnace where it is necessary to partially dismantle the furnace and laborious scraping and chiseling must be employed after the furnace has cooled to remove the accumulated material from the tubes. ent that the cracking process is only temporarily interrurted while my apparatus is being cleaned.

An additional feature of the invention is the method of joining the sections of tubing by dove-tailing or grooving them in combination with a member which serves as a. bafile plate for the hot gases of combustion flowing through the furnace and constituting the heating medium. The combining of these baffles with the joints not only makes 'the joint less likely to leak, but holds the tubes in rigid alignment making it impossible for them to warp or bend.

Other objects as well as the utility of the invention will be more apparent from the Fig. 4 is a cross sectional view taken on line 4.4: of Fig. 3.

Fig. 5 is a plan view of one of the sec tions separating the tubes.

Referring more in detail to the drawings, the outer shell or casing 1 may be constructed of the usual material for furnaces It will be readily apparsuch as brick, and may be provided with a combustion chamber 2 where any suitable fuel, such as oil, may be introduced to the burner 26 and burned in the said chamber 2. The furnace may be divided into two sections by the wall 5, one section containing a bank of connected tubes 3 and the other containing a second bank of connected tubes 4. The latter tubes are preferably made of a material refractory to welding and possessing fair heat conductivity, such as carborundum. The gases of combustion pass from combustion chamber 2 through the opening 27 into the section containing the tubes 4 where they flow upwardly in a path determined by the battles 21, imparting heat to the tubes. The hot gases pass out of this section through opening 6 into the other tube section where they flow downwardly, coming in contact with the tubes 3 and passing out through the opening 7 into a suitable stack or flue (not shown).

The oil to be treated may be introduced in a liquid state into the metal tubes 3 at 8, which are connected in series. The flow of the oil may be accelerated by a suitable force pump (not shown). The oil flows upward in the tubes. Such fiow being counter-current to the flow of the hot gases of combustion the temperature of the oil is gradually increased and is at its maximum temperature when it leaves the tubes 3. The hot oil leaves the tubes 3 at 9 (Fig. 2) and flows through transfer line 10 into chamber 11, which may be insulated to prevent heat loss, wherein the heavier fractions are allowed to separate from the vapor fractions. The vapors are then passed through line 12 and through branches l3 and 14 which communicate with the distributing chamber 17 which communicates with the large tubes l which are arranged in parallel. The vapors enter the large tubes 4: and flow downward. As they travel downward they are subjected to an increasing temperature as the gases of combustion are at their maximum temperature at the lower end of the tubes. The temperature of the vapors may be from 1100 to H0O F. when they pass out lines 18 and are transferred to a conventional type of soaking chamber (not shown), where they are allowed plenty of time in which to react. This chamber also catches a substantial portion of the carbon formed. The vapors are then passed through any of the conventional type of fractionating elements where the desired separation occurs.

The tubes at are of a comparatively large diameter to accommodate a large volume of vapors. Carborundum will largely meet the requirements since this material will with stand a temperature much higher than will be required in operation of the apparatus and also because it possesses relatively high heat ctmducting properties. It will be possible therefore to raise the temperature of the vapors materially by conduction. The lower portion of the tubes may be heated to a bright red, if desired, thus effecting heating of the vapors by radiation, which in heating the vapors to a temperature varying from 1100 to letOO F. will be more effective than heating by conduction alone.

The tubes 4 may be in short lengths or sections which may be joined by a tongue and groove fitting 19 (Fig. 4), formed in the end of each section. A suitable filler may be placed in the groove to insure it being gas or vapor tight. The batlle plates 21 have grooves 22 where they contact the tubes. A second seal against leaks from the tubing joints may be effected by packing a suitable tiller in the groove The battle plates 21 rest against the walls 1 of the furnace and are supported by a ledge 23. The battles also serve to hold the sections of the tubes in vertical position and alignment.

The method of cleaning the tubes is comparatively simple and very effective. Steam is admitted into the tubes at 26 so as to flush out all the vapors. The cover 24 is removed and air is then forced through the tubes at 26, while the tubes are heated to a high temperature. The carbon in the tubes will be completely burned and the air and products of combustion will pass out the port 25. It may be necessary to start the burning of the carbon by the introduction of steam or oxygen, or under some conditions it may be that oxygen will have to be used for the complete operation.

The apparatus is designed to work at substantially atmospheric pressure. It may be operated at slightly less than atmospheric pressure, so that any leakage at the joints would constitute a slight flow of the combustion gases into the tubes. This pressure condition may be controlled by a gas exhausting pump beyond the furnace.

I claim as my invention:

1. An apparatus for cracking hydrocarbon oil vapors, comprising in combination, a furnace and connected sections of tubing forming a continuous passageway mounted therein, said sections being constructed of carborundum.

2. An apparatus for cracking hydrocarbon oil vapors, comprising in combination, a furnace and connected sections of tubing forming a continuous passageway mounted therein, said sections being detachably con nected and constructed of carborundum.

3. An apparatus for cracking hydrocarbon oil vapors, comprising in combination, a furnace and vertically.disposed connected sections of tubing forming a continuous passageway having an inlet and an outlet and mounted in said furnace, said sections being detachably connected and constructed. of carborunduzn.

4. An apparatus for cracking hydrocarbon oil vapors, comprising in combination, a furnace and superimposed connected sections of tubing forming continuous passageways having an inlet and an outlet and mounted in said furnace, said sections being constructed of carborundum, baffles alternately disposed and positioned adjacent the points of connection between the sections adapted to impart a circuitous travel to heated combustion gases.

5. An apparatus for cracking hydrocarbon oil vapors, comprising in combination a furnace and superimposed connected sections of tubing forming continuous passageways having an inlet and an outlet and mounted in said furnace, said sections being joined together in a detachable sleeve-like engagement and constructed of carborundum, baflies, alternately disposed and positioned adjacent the points of connection between the sections adapted to impart a circuitous travel to heated combustion gases.

6. An apparatus for cracking hydrocarbon oil vapors, comprising in combination a furnace and superimposed connected sections of tubing forming continuous passageways mounted in said furnace, said sections being constructed of carborundum, bafiies positioned adjacent the points of connection between the sections in such manner as to seal the joints of the said sections of tubing.

7. An apparatus for cracking hydrocarbon oil vapors, comprising in combination a furnace and superimposed connected sections of tubin forming continuous passageways mounted in said furnace, said sections being joined together in a detachable sleeve-like engagement and constructed of carborundum, baflies positioned adjacent the points of connection between the sections in such a manner as to seal the joints of the said sections of tubing.

8. An apparatus for cracking hydrocarbon oil vapors, comprising in combination a furnace and superimposed connected sections of tubing forming continuous passageways mounted in said furnace, said sections being jointed together in a detachable engagement and constructed of carborundum, baffles positioned adjacent the points of connection between the sections, said baffles being so grooved to seal the joints of the said sections of tubing.

In testimony whereof I affix my signature.

OSCAR H. FAIRCHILD. 

